Connectors



G. G. NESBITT May l, 1962 CONNECTORS 2 Sheets-Sheet 1 Filed Jan. 20,1958 INVENTOR, George G. Nesb/'H AT TOR N EYS G. G. NESBITT May 1, 1962CONNECTORS 2 Sheets-Sheet 2 Filed Jan. 20, 1958 LLM F ign-8 INVENTOR.

ATTORNEYS aired titates atet duce 3,631,727 Patented May 1, 1%623,03L727 CNNEQTRS George G. Nesbitt, Denver, Colo., assigner to DenverWood Products Company, Denver, Colo., a corporation oli lolorado Filedlian. 20, 1953, Ser. No. 709,818 3l Claim. (6l. Ztl- 92) This inventionrelates to connectors and more particu larly to connector plates forabutting structural members whereby the structural members may berigidly and securely fastened together and retained in abuttingrelation.

ln home construction it has been determined that detinite savings inmaterial and labor requirements may be made through the use ofpre-assembled units, such as Wooden roof trusses, wall panels and thelike. Thus using pre-assembled Wooden roof trusses provides oneeiiective means of reducing the cost of small dwelling constructions.Where short spans from Wall to Wall are designed in a building, forexample 25 to 35 feet, the use of the pre-assembled trusses can resultin a cost saving in labor and, also, a reduction in the total amount oflumber utilized as compared with conventional rafter and joistconstruction. In addition to these savings in material and labor, suchpre-assembled roof trusses otter advantages of flexibility in planningand in the speed and efficiency of erection procedures at the buildingsite.

While many types of pre-assembled wooden roof trusses have beenproposed, the most commonly used pre-assem` bled device is a singleplane truss, that is one in which the major load supporting members arein a single plane. The members of the truss are joined together by somesort of connectors such as metal plates, plywood gussets, and the like.Such trusses are usually manufactured at a plant and then transported tothe building site.

Included among the objects and advantages of the present invention is toprovide a connector plate which may be utilized as a connector forabutting structural members. The plate is made of relatively thin metalbut its construction makes it strong and it produces a strong jointbetween structural members. The connector plate of the inventionprovides a quick and easily used centering means for permitting the useof a nailing gun, thereby `ermitting the construction of trusses orpanels in the ield without the use of expensive jigs, presses and thelike. The connector plate provides means for applying uniform pressureon each of the members of the joint regardless of the dimension of thestructural members, and, also,.for applying a uniform pressure on eachnail. A novel heel plate for a wooden truss is provided which joins thetruss members together at the heel, and, also, provides a positioningmeans for the truss on wall sections.

These and other objects and advantages of the invention may be readilyascertained by referring to the following description and appendedillustrations in Which:

FEC. l is a side elevational view of a section of the connector plateshowing the construction of nail holes and embossed guide in enlargeddetail;

FIG. 2 illustrates one method of producing heel plates, according to theinvention, from a strip of sheet metal;

FlG. 3 is a detailed View of an apex or ridge joint of a single planetruss member utilizing a plate according to the invention;

FIG. 4 is a side elevational view of a clear span truss member utilizingthe connector of the invention;

FIG. 5 is a perspective View of a heel plate form of th connector of theinvention; j

FlG. 6 is a perspective view of a heel plate showing a modified trussconstruction and illustrating the novel truss positioning means;

FIG. 7 is a perspective View of a nailing gun and its positioning meansfor use with a connector plate according to the invention; and

FIG. 8 is a plan view of a section of joined nails for use in the gun ofFIG. 7.

In general the connector plate of the invention comprises a piece ofsheet metal having a plurality of nail holes punched therethrough fromthe top side, leaving the underside of the sheet with a plurality ofjagged projections through which a nail may be inserted. Each nail holehas an embossed, concentric ring around the hole spaced a sufficientdistance therefrom to leave an annular portion of the original sheet inits original plane inside the ring. The plates may be made in anydesired shape, but the most common forms are rectangular andtrapezoidal. A heel connector plate for the heel joint of a single planetruss according to the invention may be readily prepared from a strip ofsheet metal. The plates are arranged with fold lines and have aplurality of nail holes with embossed guide members. The fold linespermit bending the plate so as to encompass three sides of a heel jointof a single plane truss, and includes a tab which is arranged to lieflush with one side of a Wall partition. When the tab is pulled outperpendicular to the plate, there is provided an anchor and an automaticpositioning member for the truss on supporting Wall sections.

The gusset or connector plate of the invention is illustrated in detailin FIGS. 1 and 2, and in FIG. 1 there is shown a section of a portion ofthe plate 10. The plate is preferably 20 gauge, galvanized orgalvanealled steel, having a thickness of about 0.0359 inch. Spacedthroughout the plate is a series of punched out nail holes l1 having asmall diameter hole 12 which is of a size to grip the nails used forfastening the plate to a structural member. Each nail hole has aplurality of jagged, pointed projections 13 which result from the metalbeing pushed and ruptured during the formation of the hole. Theprojections 13 are irregular and sharp and extend a short distancebeyond the surface of the plate. The holes l2 are such a size as togrippingly engage a sixpenny nail which is the nail most commonly usedwith the connector plate. Concentrically surrounding each nail hole andextending in a direction opposite from the nail holes is an embossedring 14 having an outside diameter A of approximately 1%@ of an inch, amaximum height of the tip of the embossed ring is approximatelyone-quarter of an inch above the bottom of the plate. As illustrated inFIG. 3, the nail holes with their embossed rings are staggered alonghorizontal and lateral lines so that the holes are not positionedclosely adjacent each other, and are thus arranged so that the nailswill engage the abutting members of a joint and so as not to fallclosely together in the same Woodgrain. Even with a substantial changein angle of interception of the various members, for example angles Dand C between brace member 20 and the upper cord member 21 of the ridgeconnector, the nails engage the structural members andare not positionedclosely together.

In connecting a plate to Wooden members, a nailing gun, which may be ofcompressed air, electric or other type of nailing gun, may be used todrive a nail through the hole 12 into the wooden member. One veryeffective gun for use in nailing the plate to structural members is aCyclomatic Pneumatic nailer 30 made by the California Wire Corporation,which utilizes one and one-half inch long siXpenny T nails 36. T nails36 are so called because instead of having a circular head, they have alateral head 37 not substantially greater in width than the Width of thenail, which permits the nails to be glued or otherwise secured togethermuch in the fashion of the staples of an ofce stapler. The pneumaticnailer 30 contains a magazine 35 in which a plurality of thejoinedtogether T nails 36 may be inserted and the nailer used in amanner of a stapler.

The stapling gun or nailer 3i) is shown in FIG. 7 where the pneumaticgun is supplied with air from an air hose 3l connected through thehandle 32. The compressed air operates a Vpneumatic piston for forcingthe nails through an outlet. The nose 34 of the nailer is curved at 33so as to fit around the circular embossed ring around each nail hole onthe plate. The inside curve 33 of the nose 34 corresponds to thecurvature of the embossed ring so that the nail discharge hole of thegun is centered above the nail hole 12 of the plate. A magazine 3S holdsa supply of nails attached together for use in the machine.

In one form, a plate 40, FIG. 3, is a rectangular plate having aplurality of the nail holes and embossed circles therearound arranged tohold the ridge joint or connection of a truss, FIG. 4, consisting ofupper chord members 21 and 22 and lower chord members 26 joinedtogether. The holes in the plates are arranged so as to provide anail'hole directly above the wooden members of trusses, even when thereare various pitched roofs. The braces and 23 may be at various angles,shown by angles D and C. In this case the plate 4t) is made large enoughto provide a secure fastening for the joint of all four wooden members.

In making a prefabricated truss, a plate 40 is placed on one side of theridge joint of the wooden members, which have been cut to size andpositioned, preferably in a simple jig. The plate 40 is nailed in placeby means of the nailing machine. In turn each joint has a plate nailedin position, .as plates i2 over the joint of the supports and thechords. Heel plates 4i-4 are nailed in position. The truss is thenturned over and another plate 4t) is placed on the opposite side of thetruss in rnirror image relationship to the plate 461 in place on theridge to provide a connector on each side of a single plane truss.Another plate 42 is placed on the opposite side of the truss alignedwith the corresponding one over the particular joint. In the truss shownin full in FIG. 4, the upper chord members 22 and 2l form the roofsupporting members above the rafter members 26. The rafter members 26are joined by a rectangular plate 4i and additional braces 24 and 25 areconnected in place by means of connector plates 42 which are -arrangedto hold the brace members on the respective support members. The heelplates 44 are of a special shape, illustra-ted in detail below, and theyare arranged to hold the heel joint of the truss.

The heel plate 44 is a trapezoidal piece of sheet metal having aplurality of nail holes centered in embossed rings and positionedthroughout its extent. The nail holes are arranged in position to alignthe nail into the wooden members even for various pitched roofs. InFIGS. 5 and 6 two different pitched roofs are illustrated,

where FIG. 5 shows a lower pitched roof than in FIG. 6.

In `FIG. 5 the upper edge 47 of the plate is shown out of alignment withthe top edge of the Wooden member 22, and in FIG. 6 it is shown inalignment showing the different roof pitches. are so positioned as toprovide in the upper chord suftlcient wood into which the nail may bedriven for adequate holding. In a similar manner the holes in the lowerpart of the heel plate are arranged to hit solid Wood on the lower chordto provide secure holding for nails which are driven through the holes.Both sides of the heel joint are covered by the heel plate.

As manufactured, the plates 44 are cut from a single strip of material,illustrated in FIG. 2, in adjoining trapezoidal arrangement, theadjacent members being reversed to reduce the waste of material. The cutlines 48 are arranged at the correct angle to provide a trapezoidalshape. A pair of fold lines 49 are provided generally centerwise of eachplate, spaced apart the thickness of In each case, however, the nailholesl the bottom chord, providing means for turning up the two outeredges, shown in FIGS. 4 and 6, for extending around the heel joint ofthe truss. A three-sided cut 50 in the narrow center area of the platebetween the fold lines, leaves a tab 5l cut out of the plate. The tabmay be shortened to less than the length of the three-sided cut or itmay be left the same length, depending on the use to which it is to beput. The tab 51 is supplied with punched out nail holes 52 arranged inspaced positions therein. The tab 51 is maintained in the plane of thecenter area of the plate until the prefabricated truss is placed inposition spanning wall members 53, shown in FIG. 6. When the truss is inposition, the tab 5i is pulled down in alignment with the inner surfaceof the wall and then is nailed to the wall with the nails being drivenperpendicularly into the top plate of the wall. Any vertical movement ofthe truss subjects the anchoring nails primarily to shear stresses. Thisnot only anchors thel truss to the walls, but positions the truss on thewalls maintaining exact spacing for the span. Since the chord membersare precut and the trusses preassembled, their dimensional tolerancesmay be maintained very low, providing exact spacing of the wall members.

The truss made with the plates may be assembled in the field, since theautomatic nailer is easily transported and a source of compressed airmay be, likewise, readily available at the building site. By utilizingsuch a nailing gun with the plate of the invention, the same amount ofpressure is exerted on each nail and on the plate surrounding the nailregardless of whether or not the lumber is exactly dirnensioned.Therefore, the plate may be used when abutting members are not exactlythe same thickness and the holding power ofeach nail will be the same.The projections i3 bite into the wood when a nail is driven through theplate, increasing the area of Contact and thereby increasing the holdingpower of the nail. The nails are tightly held in the plate resulting ina very strong connection.

In an actual test trusses were made from such plates similar to the oneshown in FIG. 4. Several 28 feet span trusses with a 4/ 12 roof pitchwere fabricated using the connector plates at the points shown. In orderto test the trusses under actual conditions which might be encountered,the three trusses were installed on a small section of stud wall on 24inch centers. Half inch plywood sheathing was installed on the upperchords simulating a roof sheathing. One-half inch dry wall was installedon the rafter or lower chords, simulating a ceiling. All the nailing ofthe sheathing surfaces was done in strict accordance with the standardpractice of housing. The three trusses were braced to prevent side sway,and a load was applied in increments of approximately eleven poundspersquare foot. As each increment of the load was applied, deflectionmeasurements were made, and after the loading was completed the liveload was removed and the deflection readings were again taken to see howmuch permanent set remained in the truss. The maximum effective liveload was approximately ll9 pounds per square foot, or 3.96 times thedesign live load. Under the maximum live load the maximum deflection atthe mid-point of the center truss was 1.78 inches,` which is thedeflection under approximately four times the design load. After thetests were completed, one of the heel connectors was removed and thenail holes in the wood inspected. The nail holes in the lower chord wereelongated approximately two times their normal diameter, but the nailsin the upper chord member were not noticeably deformed, indicating thatno excessive load had been imposed on the material in bearing throughthe connector plate. The connector plate then was tested to determinatethe holding power of the nails. On the test of a plate made with 2Ogauge steel, the holding power was shown to be 255 pounds per nail,while the maximum strength developed was 299 pounds and miuimumwas 217pounds per nail. Assuming a factor safety of 2.5 the maximum design loadeach nail is about 102 pounds, providing an exceptionally strong holdingpower for a nail with an excellent margin of safety. Since thev nailsare tightly held in the plate, the plate contributes to the strength ofthe joint.

While the invention has been described by reference to specificembodiments, there is no intent to limit the spirit and scope of theinvention to the precise details so set forth, except insofar as definedin the following claim.

I claim:

A heel plate connector for joining the heel joint of abutting upper andbottom wooden truss members lying in the same plane and each heel plateconnector arranged for resting on a wall section for anchoring acompleted truss to such a wall section at substantially right angles tosaid bottom truss member, comprising a sheet of metal having a pair ofsubstantially parallel planar polygonal portions attached atsubstantially right angles to an intermediate planar portion, saidplanar polygonal portions arranged to overlie a substantial portion ofthe heel joint of said abutting members for nailed connection theretothrough a plurality of nail receiving openings spaced in rows throughoutthe extent of said planar polygonal portions, said planar polygonalportions tapering across their upper edges whereby they are encompassedwithin the external surfaces of the truss to be joined, each nailreceiving opening being encompassed by a concentric annular ring spacedfrom the opening and projecting outwardly from one face of the sheet anda circumferential portion bordering each nail receiving opening andextending outwardly from the opposite face of the sheet, the sheet metalbetween each said nail receiving opening and its concentric annular ringforming an annular bearing portion in position to bear against a memberinto which nails are driven through said nail receiving opening andarranged to support the headed portion of said nails and apply uniformpressure against said member into which the nails are driven, theintermediate planar portion having a pair of spaced apart slits adjacentits sides and extending through a portion thereof and terminating withinits ends and having another slit interconnected with said pair of slitsto detine at least one displaceable pull-out tab of substantial strengthand in which one end of the pull-out tab is interconnected with oneportion of said intermediate planar portion, there being end portions ofsaid intermediate planar portion interconnecting said polygonalportions, and each end portion of the intermediate planar portioninterconnecting said planar polygonal portions being of sufficientextent and strength to Substantially counteract twisting movementbetween said planar polygonal portions when secured to upper and bottomtruss members.

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